ESTIMATION OF THE VARIATION IN APPARENT DISPLACEMENT ALONG NORMAL-FAULT TRACES REFRACTED BY DIFFERENTIAL COMPACTION

Initially planar fault surfaces can be refracted by differential compaction, sudden changes in the displacement gradient taking place at the contact of different lithologies. As a result, the original displacement pattern, e.g. a cone-type in an idealized case, can be changed into a zigzag-type, especially when the initial dip angle of the fault and differential compaction are high. Compared with pre- and syn-faulting compaction, post-faulting compaction is more likely to change the initial displacement pattern along normal faults which were active near the sediment surface. Based upon the assumption that compaction is homogeneous vertical strain, the original fault geometry and displacement pattern can be estimated by means of decompaction and related geometric calculations.